Jurassic-Cretaceous Tectonic Evolution of the Southeastern Gulf of Mexico, Constrains on to the Style and Timing of the Gulf of Mexico Rift-Drift Development

Abstract

Abstract

The Southeastern Gulf of Mexico has been a seaway connecting the Gulf of Mexico with the Caribbean since the late Jurassic. Historical academic seismic data and the results of the DSDP Leg 77, collected in the 1980-81, was utilized to carry out detailed tectonic analysis and to help to understand how the evolution of this area is related to the opening of the Gulf of Mexico basin.

Researchers agree that the during the Late Triassic? to late Middle Jurassic continental extension phase, the stable Yucatan block rifted away from North America above a southward dipping crustal detachment. During the Callovian to Berriasian oceanic phase, however, to accommodate the newly formed oceanic crust in the Gulf of Mexico, the relatively stable Yucatan block rotated counterclockwise about 42 degrees around a pole close to the Pinar del Rio Knoll, just north from the present day Cuba.

Salt was deposited in the Gulf of Mexico in the Callovian to early Oxfordian? time above thinned continental and over the newly formed oceanic crust in the central Gulf. Lack of salt in both the oceanic and continental segments of the Southeastern Gulf of Mexico clearly indicates that the northern (oceanic) portion is younger than Callovian and that southern (continental) portion of the rift didn't subside below sea level before the cessation of salt deposition in the Gulf of Mexico. Thus, the documented southward propagating rift in the Southeastern Gulf of Mexico, between Yucatan and Florida, fully developed only during the rotation of the Yucatan peninsula. In other words, the formation of the Southeastern Gulf of Mexico propagating rift and the formation of oceanic crust in the Gulf of Mexico are time equivalent. Based on the observed regional post-rift unconformity, dated in the DSDP Hole-535, the Yucatan block reached its current position is Upper Berriasian. Consequently, the Berriasian unconformity signals the completion of oceanic crust formation in the Gulf of Mexico.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016